Dielectric ceramic composition

ABSTRACT

Disclosed herein is a dielectric ceramic composition based on a lead-based perovskite-type complex compound containing nickel, characterized in that the amount of nickel is smaller than the stoichiometric amount. The dielectric ceramic composition can contain α mol % (0&lt;α≦100) of lead-based perovskite-type complex compound represented by the formula below 
     
         Pb Ni.sub.(1-x)/3 A.sub.2/3 !.sub.a  Ni.sub.(1-y)/2 D.sub.1/2 !.sub.(1-a) 
    
      O 3   
     where A denotes at least one element selected from elements having a valance of +5, D denotes at least one element selected from elements having a valance of +6, 0&lt;x&lt;1, 0&lt;y&lt;1, and 0≦a≦1, with the amount of nickel being γ mol % (0&lt;γ≦20) which is smaller than the stoichiometric amount (where γ=α×(a×x×1/3+(1-a)×y×1/2)). The dielectric ceramics composition which has a high dielectric constant and yet has nearly constant capacity-temperature characteristics.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a dielectric ceramics compound.

2. Description of the Related Art

Barium titanate series ceramics have been in general use as a highdielectric material in electronic parts such as for ceramic capacitors.Unfortunately, they have such a high firing temperature (1300°-1400° C.)that laminated ceramic capacitors employing these need internalelectrodes of expensive platinum or palladium.

Although there have been available materials having nearlytemperature-independent properties, they are not suitable for capacitorsbecause of their low dielectric constant (about 2000 at the highest).

There has recently been reported lead-based perovskite-type complexcompounds as a high dielectric material capable of sintering at lowtemperatures. These include ternary ones composed of leadmagnesium-niobate Pb(Mg_(1/3) Nb_(2/3))O₃, lead nickel-niobatePb(Ni_(1/3) Nb_(2/3))O₃, and lead titanate PbTiO₃. These have anextremely high dielectric constant but suffer the disadvantage offluctuating somewhat in the value with temperature.

OBJECT AND SUMMARY OF THE INVENTION

The present invention was completed in view of the foregoing. It is anobject of the present invention to provide a dielectric ceramicscomposition which has nearly constant capacity-temperaturecharacteristics despite its high dielectric constant.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The dielectric ceramics composition of the present invention is based ona lead-based perovskite-type complex compound containing nickel which ischaracterized in that the amount of nickel is smaller than thestoichiometric amount.

In a preferred embodiment of the present invention, the dielectricceramics composition contains α mol % (0<α≦100, preferably 10≦α≦52) of alead-based perovskite-type complex compound represented by the formulabelow

    Pb Ni.sub.(1-x)/3 A.sub.2/3 !.sub.a  Ni.sub.(1-y)/2 D.sub.1/2 !.sub.(1-a) O.sub.3

(where A denotes at least one element having a valance of +5, D denotesat least one element having a valance of +6, 0<x<1, 0<y<1, 0≦a≦1, withthe amount of nickel being γ mol % (0<γ≦25, preferably 0.48≦α≦20) whichis smaller than the stoichiometric amount (whereγ=α×(a×x×1/3+(1-a)×y×1/2)).

In the following, the embodiments of the present invention areexplained.

The dielectric ceramics composition of the present invention is based ona lead-based perovskite-type complex compound containing nickel which ischaracterized in that the amount of nickel is smaller than thestoichiometric amount.

The fact that the amount of nickel is smaller than the stoichiometricamount required to form the perovskite structure is responsible for thedielectric ceramics composition which has nearly constantcapacity-temperature characteristics despite its high dielectricconstant.

An example of the dielectric ceramic composition according to thepresent invention is one which is based on a lead-based perovskite-typecomplex compound represented by the formula below

    Pb Ni.sub.(1-x)/3 A.sub.2/3 !.sub.a  Ni.sub.(1-y)/2 D.sub.1/2 !.sub.(1-a) O.sub.3

where A denotes at least one element having a valance of +5, D denotesat least one element having a valance of +6, 0<x<1, 0<y<1, and 0≦a≦1. Aand D in the formula above are exemplified by Nb and Ta, and W,respectively.

The dielectric ceramic composition may contain the above-mentionedlead-based perovskite-type complex compound in an amount of α mol %(0<α≦100), in which case the amount of nickel should be γ mol % (0<γ≦25)and which is smaller than the stoichiometric amount (whereγ=α×(a×x×1/3+(1-a)×y×1/2)).

If the amount of nickel exceeds about 20 mol %, the resultingcomposition would have a dielectric constant lower than 3000. If theamount of nickel is zero, the resulting composition would have anextremely low dielectric constant which is not desirable. The amount ofnickel should preferably be γ mol %, with γ most preferably in the rangeof 0<γ≦10.

The invention will be described in more detail with reference to thefollowing examples which are not intended to restrict the scope of theinvention.

EXAMPLES

Samples of the dielectric ceramic composition of the present inventionwere prepared according to different formulations.

Each sample was prepared from Pb₃ O₄, NiO, Nb₂ O₅, TiO₂, MnO, CuO andWO₃, whose amounts were so selected as to establish the desiredcomposition. These starting materials were mixed by wet ball-milling.The resulting mixture was dried and then calcined at 750° C. for 2hours. The resulting powder (100 pbw) was mixed with vinyl acetate (5pbw) as a binder by wet ball-milling. The resulting mixture was driedand crushed into powder. The powder was formed into a disk, 10 mm indiameter and 1.2 mm thick, by compression under a pressure of 2.5 t/cm².The disk was fired in an atmosphere of Pb by using an electric furnace.The fired disk was provided with an electrode formed from Ag paste bybaking.

The thus prepared sample was measured for dielectric constant (ε) anddielectric loss (tan δ) at 1 kHz, 1 V, and 20° C. The sample was alsomeasured for resistivity, with a voltage of 250 V applied for 2 minutes.The sample was tested for capacity-temperature characteristics at 1 kHzand 1 V. The capacity-temperature characteristics is expressed as thechange (%) in capacity that occurs when the temperature is raised orlowered by 50° C. from the reference temperature at which the capacityis maximum. The expression in this manner is more convenient forcomparison of samples than the rate of change in capacity at -25° C. and+85° C. because some samples have the transition point away from normaltemperature.

The samples vary in the amounts of principal and auxiliary components,the firing temperature, and the electrical properties as shown in Tables1 to 8. Incidentally, the amount (wt %) of auxiliary components is basedon the amount (as 100%) of principal components.

In Table 1 to 8, α denotes the lead-based perovskite-type complexcompound containing nickel and β1 and β2 denote a lead-basedperovskite-type complex compound not containing nickel.

Each amount (in mol %) of α, β1, and β2 are such that their total amountis 100 mol %, although their ratio is arbitrary.

                                      TABLE 1                                     __________________________________________________________________________        Lead-based perovskite-type complex                                            compound containing nickel                                                                            Lead-based                                            α = Pb Ni.sub.(1-x)/3 A.sub.2/3 !.sub.a  Ni.sub.(1-y)/2                 D.sub.1/2 !.sub.(1-a) O.sub.3                                                                         perovskite-type complex                           Sample                                                                            γ = α × (a × x × 1/3 + (1 - a) ×          y × 1/2)          compound not containing nickel                    No. α (mol %)                                                                    a x   A y   D  γ                                                                           β1                                                                           mol %                                                                             β2                                                                         mol %                                   __________________________________________________________________________     1 *                                                                              72   1 -0.04                                                                             Nb       -0.96                                                                             PbTiO.sub.3                                                                       28                                             2 *                                                                              72   1 0   Nb       0.00                                                                              PbTiO.sub.3                                                                       28                                             3  72   1 0.02                                                                              Nb       0.48                                                                              PbTiO.sub.3                                                                       28                                             4  72   1 0.04                                                                              Nb       0.96                                                                              PbTiO.sub.3                                                                       28                                             5  72   1 0.06                                                                              Nb       1.44                                                                              PbTiO.sub.3                                                                       28                                             6  72   1 0.12                                                                              Nb       2.88                                                                              PbTiO.sub.3                                                                       28                                             7  72   1 0.2 Nb       4.80                                                                              PbTiO.sub.3                                                                       28                                             8  72   1 0.3 Nb       7.20                                                                              PbTiO.sub.3                                                                       28                                             9  72   1 0.5 Nb       12.00                                                                             PbTiO.sub.3                                                                       28                                            10  72   1 0.7 Nb       16.80                                                                             PbTiO.sub.3                                                                       28                                            11  72   1 0.9 Nb       21.60                                                                             PbTiO.sub.3                                                                       28                                            12 *                                                                              50   0.4                                                                             0   Nb    W  0.00                                                                              PbTiO.sub.3                                                                       50                                            13  50   0.4                                                                             0.06                                                                              Nb                                                                              0.06                                                                              W  1.30                                                                              PbTiO.sub.3                                                                       50                                            __________________________________________________________________________

                                      TABLE 2                                     __________________________________________________________________________                                             Change of                                                                           Change of                                                               capacity at                                                                         capacity at                                                             reference                                                                           reference                                           Firing              temperature                                                                         temperature                    Sample                                                                            Amounts of auxiliary components                                                                tempera-                                                                           Dielectric                                                                         Dielectric                                                                         Resistivity                                                                        minus 50° C.                                                                 plus 50° C.             No.    wt %       wt %                                                                             ture (°C.)                                                                  constant                                                                           loss (%)                                                                           (Ω cm)                                                                       (%)   (%)                            __________________________________________________________________________     1 *                                                                              MnO                                                                              0.1                                                                              Pb(Cu.sub.1/2 W.sub.1/2)O.sub.3                                                       3  1000 14200                                                                              0.22 7.9 × 10.sup.12                                                              -50.2 -32.2                           2 *                                                                              MnO                                                                              0.1                                                                              Pb(Cu.sub.1/2 W.sub.1/2)O.sub.3                                                       3  1000 13600                                                                              0.25 7.6 × 10.sup.12                                                              -46.3 -28.0                           3  MnO                                                                              0.1                                                                              Pb(Cu.sub.1/2 W.sub.1/2)O.sub.3                                                       3  1000 12100                                                                              0.51 6.8 × 10.sup.12                                                              -34.2 -25.4                           4  MnO                                                                              0.1                                                                              Pb(Cu.sub.1/2 W.sub.1/2)O.sub.3                                                       3  1000 10300                                                                              0.62 6.9 × 10.sup.12                                                              -15.8 -24.1                           5  MnO                                                                              0.1                                                                              Pb(Cu.sub.1/2 W.sub.1/2)O.sub.3                                                       3  1000 9200 0.65 5.1 × 10.sup.12                                                              -16.2 -23.2                           6  MnO                                                                              0.1                                                                              Pb(Cu.sub.1/2 W.sub.1/2)O.sub.3                                                       3  1000 7900 0.70 5.5 × 10.sup.12                                                              -15.7 -21.5                           7  MnO                                                                              0.1                                                                              Pb(Cu.sub.1/2 W.sub.1/2)O.sub.3                                                       3  1000 6800 0.74 4.9 × 10.sup.12                                                              -14.2 -17.2                           8  MnO                                                                              0.1                                                                              Pb(Cu.sub.1/2 W.sub.1/2)O.sub.3                                                       3  1000 5400 1.23 4.2 × 10.sup.12                                                              -11.2 -12.1                           9  MnO                                                                              0.1                                                                              Pb(Cu.sub.1/2 W.sub.1/2)O.sub.3                                                       3  1000 4300 1.30 3.6 × 10.sup.12                                                              -10.5 -11.2                          10  MnO                                                                              0.1                                                                              Pb(Cu.sub.1/2 W.sub.1/2)O.sub.3                                                       3  1000 3200 1.35 3.1 × 10.sup.12                                                               -8.6  -9.8                          11  MnO                                                                              0.1                                                                              Pb(Cu.sub.1/2 W.sub.1/2)O.sub.3                                                       3  1000 2500 1.41 3.2 × 10.sup.12                                                               -7.9  -8.7                          12 *                 1000 9600 2.30 2.7 × 10.sup.12                                                              -38.6 -30.5                          13                   1050 7200 2.39 3.5 × 10.sup.12                                                              -32.5 -28.6                          __________________________________________________________________________

                                      TABLE 3                                     __________________________________________________________________________        Lead-based perovskite-type complex                                            compound containing nickel                                                    α = Pb Ni.sub.(1-x)/3 A.sub.2/3 !.sub.a  Ni.sub.(1-y)/2                 D.sub.1/2 !.sub.(1-a) O.sub.3                                                                     Lead-based perovskite-                                Sample                                                                            γ = α × (a × x × 1/3 + (1 - a) ×          y × 1/2)      type complex compound not containing nickel           No. α (mol %)                                                                    a x  A y D γ                                                                           β1                                                                           mol %                                                                             β2 mol %                                 __________________________________________________________________________    14 *                                                                              45   1 0  Nb    0.00                                                                              PbTiO.sub.3                                                                       25  Pb(Mg.sub.1/3 Nb.sub.2/3)O.sub.3                                                      30                                    15  45   1 0.04                                                                             Nb    0.60                                                                              PbTiO.sub.3                                                                       25  Pb(Mg.sub.1/3 Nb.sub.2/3)O.sub.3                                                      30                                    16  45   1 0.1                                                                              Nb    1.50                                                                              PbTiO.sub.3                                                                       25  Pb(Mg.sub.1/3 Nb.sub.2/3)O.sub.3                                                      30                                    17  45   1 0.2                                                                              Nb    3.00                                                                              PbTiO.sub.3                                                                       25  Pb(Mg.sub.1/3 Nb.sub.2/3)O.sub.3                                                      30                                    18  45   1 0.3                                                                              Nb    4.50                                                                              PbTiO.sub.3                                                                       25  Pb(Mg.sub.1/3 Nb.sub.2/3)O.sub.3                                                      30                                    19  45   1 0.35                                                                             Nb    5.25                                                                              PbTiO.sub.3                                                                       25  Pb(Mg.sub.1/3 Nb.sub.2/3)O.sub.3                                                      30                                    20 *                                                                              70   1 0  Nb    0.00                                                                              PbTiO.sub.3                                                                       25  Pb(Mg.sub.1/3 Nb.sub.2/3)O.sub.3                                                      5                                     21  70   1 0.06                                                                             Nb    1.40                                                                              PbTiO.sub.3                                                                       25  Pb(Mg.sub.1/3 Nb.sub.2/3)O.sub.3                                                      5                                     22  70   1 0.2                                                                              Nb    4.67                                                                              PbTiO.sub.3                                                                       25  Pb(Mg.sub.1/3 Nb.sub.2/3)O.sub.3                                                      5                                     23  70   1 0.4                                                                              Nb    9.33                                                                              PbTiO.sub.3                                                                       25  Pb(Mg.sub.1/3 Nb.sub.2/3)O.sub.3                                                      5                                     24  70   1 0.8                                                                              Nb    18.67                                                                             PbTiO.sub.3                                                                       25  Pb(Mg.sub.1/3 Nb.sub.2/3)O.sub.3                                                      5                                     25  70   1 0.9                                                                              Nb    21.00                                                                             PbTiO.sub.3                                                                       25  Pb(Zn.sub.1/3 Nb.sub.2/3)O.sub.3                                                      5                                     26 *                                                                              70   1 0  Nb    0.00                                                                              PbTiO.sub.3                                                                       20  Pb(Zn.sub.1/3 Nb.sub.2/3)O.sub.3                                                      5                                     27  70   1 0.06                                                                             Nb    1.40                                                                              PbTiO.sub.3                                                                       20  Pb(Mg.sub.1/3 Nb.sub.2/3)O.sub.3                                                      5                                     __________________________________________________________________________

                                      TABLE 4                                     __________________________________________________________________________                                                   Change  Change                                                                of capacity                                                                           of capacity                                      Firing               at reference                                                                          at reference           Sample                                                                            Amounts of auxiliary components                                                                     temperature                                                                         Dielectric                                                                         Dielectric                                                                         Resistivity                                                                        temperature                                                                           temperature            No.         wt %       wt %                                                                             (°C.)                                                                        constant                                                                           loss (%)                                                                           (Ω cm)                                                                       minus 50° C.                                                                   plus 50° C.                                                            (%)                    __________________________________________________________________________    14 *                                                                              Pb(Mn.sub.1/3 Nb.sub.2/3)O.sub.3                                                      1             1050  11000                                                                              1.24 2.9 × 10.sup.12                                                              -34.0   -44.9                  15  Pb(Mn.sub.1/3 Nb.sub.2/3)O.sub.3                                                      1             1050  9400 1.51 2.7 × 10.sup.12                                                              -33.0   -39.0                  16  Pb(Mn.sub.1/3 Nb.sub.2/3)O.sub.3                                                      1             1050  7800 1.56 2.5 × 10.sup.12                                                              -26.7   -24.5                  17  Pb(Mn.sub.1/3 Nb.sub.2/3)O.sub.3                                                      1             1050  5400 1.64 2.6 × 10.sup.12                                                              -20.6   -19.5                  18  Pb(Mn.sub.1/3 Nb.sub.2/3)O.sub.3                                                      1             1050  3700 1.63 2.2 × 10.sup.12                                                              -14.6   -15.3                  19  Pb(Mn.sub.1/3 Nb.sub.2/3)O.sub.3                                                      1             1050  2900 2.10 1.9 × 10.sup.12                                                               -9.5   -10.2                  20                        1050  9300 2.23 2.8 × 10.sup.12                                                              -38.9   -42.3                  21                        1050  8300 2.45 3.9 × 10.sup.12                                                              -35.6   -32.1                  22                        1050  7400 2.52 2.7 × 10.sup.12                                                              -29.4   -27.6                  23                        1050  5200 2.51 2.4 × 10.sup.12                                                              -15.2   -20.1                  24                        1050  3400 2.64 1.9 × 10.sup.12                                                              -12.5   -15.7                  25 *                      1050  1700 2.71 1.5 × 10.sup.12                                                               -9.4   -13.1                  26  Pb(Mn.sub.1/3 Nb.sub.2/3)O.sub.3                                                      0.5                                                                              Pb(Cu.sub.1/2 W.sub.1/2)O.sub.3                                                       2  1000  10500                                                                              0.29 7.2 × 10.sup.12                                                              -46.0   -29.1                  27  Pb(Mn.sub.1/3 Nb.sub.2/3)O.sub.3                                                      0.5                                                                              Pb(Cu.sub.1/2 W.sub.1/2)O.sub.3                                                       2  1000  9400 0.58 6.9 × 10.sup.12                                                              -36.1   -17.8                  __________________________________________________________________________

                                      TABLE 5                                     __________________________________________________________________________        Lead-based perovskite-type complex                                            compound containing nickel                                                    α = Pb Ni.sub.(1-x)/3 A.sub.2/3 !.sub.a  Ni.sub.(1-y)/2                 D.sub.1/2 !.sub.(1-a) O.sub.3                                                                     Lead-based perovskite-                                Sample                                                                            γ = α × (a × x × 1/3 + (1 - a) ×          y × 1/2)      type complex compound not containing nickel           No. α (mol %)                                                                    a x  A y  D γ                                                                          β1 mol %                                                                             β2 mol %                             __________________________________________________________________________    28 *                                                                              65   1 0  Nb     0.00                                                                             PbTiO.sub.3                                                                           15  PbZrO.sub.3                                                                           20                                29  65   1 0.05                                                                             Nb     1.08                                                                             PbTiO.sub.3                                                                           15  PbZrO.sub.3                                                                           20                                30 *                                                                              40   1 0  Nb     0.00                                                                             PbTiO.sub.3                                                                           30  Pb(Fe.sub.2/3 W.sub.1/3)O.sub.3                                                       30                                31  40   1 0.08                                                                             Nb     1.07                                                                             PbTiO.sub.3                                                                           30  Pb(Fe.sub.2/3 W.sub.1/3)O.sub.3                                                       30                                32 *                                                                              40   1 0  Nb     0.00                                                                             Pb(Mg.sub.1/3 Nb.sub.2/3)O.sub.3                                                      10  Pb(Zn.sub.1/3 Nb.sub.2/3)O.sub.3                                                      50                                33  40   1 0.08                                                                             Nb     1.07                                                                             Pb(Mg.sub.1/3 Nb.sub.2/3)O.sub.3                                                      10  Pb(Zn.sub.1/3 Nb.sub.2/3)O.sub.3                                                      50                                34  40   1 0.2                                                                              Nb     2.67                                                                             Pb(Mg.sub.1/3 Nb.sub.2/3)O.sub.3                                                      10  Pb(Zn.sub.1/3 Nb.sub.2/3)O.sub.3                                                      50                                35  40   1 0.4                                                                              Nb     5.33                                                                             Pb(Mg.sub.1/3 Nb.sub.2/3)O.sub.3                                                      10  Pb(Zn.sub.1/3 Nb.sub.2/3)O.sub.3                                                      50                                36 *                                                                              10   0      0  W 0.00                                                                             Pb(Mg.sub.1/3 Nb.sub.2/3)O.sub.3                                                      40  Pb(Zn.sub.1/3 Nb.sub.2/3)O.sub.3                                                      50                                37  10   0      0.1                                                                              W 0.50                                                                             Pb(Mg.sub.1/3 Nb.sub.2/3)O.sub.3                                                      40  Pb(Zn.sub.1/3 Nb.sub.2/3)O.sub.3                                                      50                                38  10   0      0.4                                                                              W 2.00                                                                             Pb(Mg.sub.1/3 Nb.sub.2/3)O.sub.3                                                      40  Pb(Zn.sub.1/3 Nb.sub.2/3)O.sub.3                                                      50                                39 *                                                                              20   0      0  W 0.00                                                                             PbTiO.sub.3                                                                           25  Pb(Mg.sub.1/2 Nb.sub.1/2)O.sub.3                                                      55                                40  20   0      0.1                                                                              W 1.00                                                                             PbTiO.sub.3                                                                           25  Pb(Mg.sub.1/3 Nb.sub.2/3)O.sub.3                                                      55                                41 *                                                                              20   0      0  W 0.00                                                                             PbTiO.sub.3                                                                           25  Pb(Mg.sub.1/3 Nb.sub.2/3)O.sub.3                                                      55                                42  20   0      0.1                                                                              W 1.00                                                                             PbTiO.sub.3                                                                           25  Pb(Mg.sub.1/3 Nb.sub.2/3)O.sub.3                                                      55                                43  20   0      0.3                                                                              W 3.00                                                                             PbTiO.sub.3                                                                           25  Pb(Mg.sub.1/3 Nb.sub.2/3)O.sub.3                                                      55                                44  20   0      0.5                                                                              W 5.00                                                                             PbTiO.sub.3                                                                           25  Pb(Mg.sub.1/3 Nb.sub.2/3)O.sub.3                                                      55                                __________________________________________________________________________

                                      TABLE 6                                     __________________________________________________________________________                                                   Change  Change                                                                of capacity                                                                           of capacity                                      Firing               at reference                                                                          at reference           Sample                                                                            Amounts of auxiliary components                                                                     temperature                                                                         Dielectric                                                                         Dielectric                                                                         Resistivity                                                                        temperature                                                                           temperature            No.         wt %       wt %                                                                             (°C.)                                                                        constant                                                                           loss (%)                                                                           (Ω cm)                                                                       minus 50° C.                                                                   plus 50° C.                                                            (%)                    __________________________________________________________________________    28 *                                                                              Pb(Cu.sub.1/2 W.sub.1/2)O.sub.3                                                       3             1000  9300 0.53 4.6 × 10.sup.12                                                              -46.9   -24.7                  29  Pb(Cu.sub.1/2 W.sub.1/2)O.sub.3                                                       3             1000  8500 0.61 3.8 × 10.sup.12                                                              -41.1   -20.1                  30 *                                                                              MnO     0.1                                                                              Pb(Cu.sub.1/2 W.sub.1/2)O.sub.3                                                       3  1000  5700 3.29 7.8 × 10.sup.12                                                              -120.0  -95.1                  31  MnO     0.1                                                                              Pb(Cu.sub.1/2 W.sub.1/2)O.sub.3                                                       3  1000  3700 4.07 5.6 × 10.sup.12                                                              -101.2  -88.1                  32 *                                                                              MnO     0.1                                                                              Pb(Cu.sub.1/2 W.sub.1/2)O.sub.3                                                       3  1000  9200 3.10 7.6 × 10.sup.12                                                              -25.6   -35.7                  33  MnO     0.1                                                                              Pb(Cu.sub.1/2 W.sub.1/2)O.sub.3                                                       3  1000  7300 3.33 8.1 × 10.sup.12                                                              -22.1   -25.6                  34  MnO     0.1                                                                              Pb(Cu.sub.1/2 W.sub.1/2)O.sub.3                                                       3  1000  6500 3.56 7.9 × 10.sup.12                                                              -15.6   -14.5                  35  MnO     0.1                                                                              Pb(Cu.sub.1/2 W.sub.1/2)O.sub.3                                                       3  1000  4300 4.23 6.8 × 10.sup.12                                                               -8.6   -10.2                  36 *                      1050  8500 2.90 4.8 × 10.sup.12                                                              -28.6   -23.6                  37                        1050  7600 3.10 4.3 × 10.sup.12                                                              -20.5   -18.6                  38                        1050  5400 3.56 3.6 × 10.sup.12                                                              -15.6   -14.2                  39 *                                                                              Pb(Mn.sub.1/3 Nb.sub.2/3)O.sub.3                                                      1             1000  11000                                                                              5.60 3.9 × 10.sup.12                                                              -48.6   -49.3                  40  Pb(Mn.sub.1/3 Nb.sub.2/3)O.sub.3                                                      1             1000  9200 6.50 3.7 × 10.sup.12                                                              -39.1   -38.9                  41 *                                                                              Pb(Mn.sub.1/2 W.sub.1/2)O.sub.3                                                       1.5           1000  9800 4.30 4.9 × 10.sup.12                                                              -45.3   -46.8                  42  Pb(Mn.sub.1/2 W.sub.1/2)O.sub.3                                                       1.5           1000  8200 4.70 4.3 × 10.sup.12                                                              -30.5   -30.8                  43  Pb(Mn.sub.1/2 W.sub.1/2)O.sub.3                                                       1.5           1000  6300 5.32 2.3 × 10.sup.12                                                              -19.7   -24.5                  44  Pb(Mn.sub.1/2 W.sub.1/2)O.sub.3                                                       1.5           1000  4900 5.95 1.5 × 10.sup.12                                                              -11.3   -12.4                  __________________________________________________________________________

                                      TABLE 7                                     __________________________________________________________________________        Lead-based perovskite-type complex                                            compound containing nickel                                                    α = Pb Ni.sub.(1-x)/3 A.sub.2/3 !.sub.a  Ni.sub.(1-y)/2                 D.sub.1/2 !.sub.(1-a) O.sub.3                                                                        Lead-based perovskite-                             Sample                                                                            γ = α × (a × x × 1/3 + (1 - a) ×          y × 1/2)         type complex compound not containing nickel        No. α (mol %)                                                                    a x  A    y  D γ                                                                          β1 mol %                                                                             β2 mol %                          __________________________________________________________________________    45 *                                                                              30   1 0  Nb        0.00                                                                             Pb(Fe.sub.1/2 Nb.sub.1/2)O.sub.3                                                      70                                         46  30   1 0.1                                                                              Nb        1.00                                                                             Pb(Fe.sub.1/2 Nb.sub.1/2)O.sub.3                                                      70                                         47  30   1 0.3                                                                              Nb        3.00                                                                             Pb(Fe.sub.1/2 Nb.sub.1/2)O.sub.3                                                      70                                         48  30   1 0.5                                                                              Nb        5.00                                                                             Pb(Fe.sub.1/2 Nb.sub.1/2)O.sub.3                                                      70                                         49 *                                                                              50   0.4                                                                             0  Nb, Ta                                                                             0  W 0.00                                                                             PbTiO.sub.3                                                                           50                                         50  50   0.4                                                                             0.08                                                                             Nb, Ta                                                                             0.04                                                                             W 1.13                                                                             PbTiO.sub.3                                                                           50                                         51 *                                                                              45   1 0  Nb, Ta    0.00                                                                             PbTiO.sub.3                                                                           25  Pb(Mg.sub.1/3 Nb.sub.2/3)O.sub.3                                                      30                             52  45   1 0.06                                                                             Nb, Ta    0.90                                                                             PbTiO.sub.3                                                                           25  Pb(Mg.sub.1/3 Nb.sub.2/3)O.sub.3                                                      30                             __________________________________________________________________________

                                      TABLE 8                                     __________________________________________________________________________                                                   Change  Change                                                                of capacity                                                                           of capacity                                      Firing               at reference                                                                          at reference           Sample                                                                            Amounts of auxiliary components                                                                     temperature                                                                         Dielectric                                                                         Dielectric                                                                         Resistivity                                                                        temperature                                                                           temperature            No.         wt %       wt %                                                                             (°C.)                                                                        constant                                                                           loss (%)                                                                           (Ω cm)                                                                       minus 50° C.                                                                   plus 50° C.                                                            (%)                    __________________________________________________________________________    45 *                                                                              MnO     0.1                                                                              Pb(Cu.sub.1/2 W.sub.1/2)O.sub.3                                                       3  1000  17200                                                                              0.34 4.5 × 10.sup.12                                                              -45.7   -57.8                  46  MnO     0.1                                                                              Pb(Cu.sub.1/2 W.sub.1/2)O.sub.3                                                       3  1000  13800                                                                              0.40 4.3 × 10.sup.12                                                              -35.6   -32.5                  47  MnO     0.1                                                                              Pb(Cu.sub.1/2 W.sub.1/2)O.sub.3                                                       3  1000  5800 0.58 2.9 × 10.sup.12                                                              -24.5   -19.8                  48  MnO     0.1                                                                              Pb(Cu.sub.1/2 W.sub.1/2)O.sub.3                                                       3  1000  3200 0.89 1.9 × 10.sup.12                                                              -14.3   -12.1                  49 *                      1070  9300 2.35 2.6 × 10.sup.12                                                              -37.5   -30.8                  50                        1070  6900 2.63 2.9 × 10.sup.12                                                              -33.4   -27.6                  51 *                                                                              Pb(Mn.sub.1/3 Nb.sub.2/3)O.sub.3                                                      1             1070  10800                                                                              1.54 3.6 × 10.sup.12                                                              -35.0   -45.3                  52  Pb(Mn.sub.1/3 Nb.sub.2/3)O.sub.3                                                      1             1070  9100 1.63 2.9 × 10.sup.12                                                              -32.1   -38.6                  __________________________________________________________________________

In Tables 1 to 8, comparative samples are marked with a star.Comparative samples Nos. 1 and 2 correspond to samples Nos. 3 to 11.Comparative sample No. 12 corresponds to sample No. 13. Comparativesample No. 14 corresponds to samples Nos. 15 to 19. Comparative sampleNo. 20 corresponds to samples Nos. 21 to 25. Comparative sample No. 26corresponds to sample No. 27. Comparative sample No. 28 corresponds tosample No. 29. Comparative sample No. 32 corresponds to samples Nos. 33to 35. Comparative sample No. 36 corresponds to samples Nos. 37 and 38.Comparative sample No. 30 corresponds to samples Nos. 31 and 32.Comparative sample No. 35 corresponds to samples Nos. 36 to 38.Comparative sample No. 39 corresponds to sample No. 40. Comparativesample No. 41 corresponds to samples Nos. 42 to 44. Comparative sampleNo. 45 corresponds to samples Nos. 46 to 48. Comparative sample No. 49corresponds to sample No. 50. Comparative sample No. 51 corresponds tosample No. 52.

It is apparent from Tables 2, 4, 6, and 8 that the samples decrease intemperature dependence of capacity while keeping the dielectric constantas the amount of nickel deviates from the stoichiometric amount. All thesamples excel their corresponding comparative samples.

The dielectric ceramics composition of the present invention is based ona lead-based perovskite-type complex compound containing nickel which ischaracterized in that the amount of nickel is smaller than thestoichiometric amount. Therefore, it has a high dielectric constant andyet has nearly constant capacity-temperature characteristics.

What is claimed is:
 1. A dielectric ceramic composition comprising alead-based perovskite-type complex compound containing nickel in whichthe amount of nickel is smaller than the stoichiometric amount and inwhich said lead-based perovskite-type complex compound is represented bythe formula

    Pb(Ni.sub.(1-x)/3 A.sub.2/3).sub.a (Ni.sub.(1-y)/2 D.sub.1/2).sub.(1-a) O.sub.3

where A denotes at least one element having a valance of +5, D denotesat least one element having a valance of +6, 0<x<1, 0<y<1, 0≦a≦1, andthe amount of nickel is γ mol % which is smaller than the stoichiometricamount, where γ=α×(a×x×1/3+(1-a)×y×1/2), 0<α≦100 and 0<γ≦25.
 2. Adielectric ceramic composition as defined in claim 1 in which A is Nb orTa, and D is W.
 3. A dielectric ceramic composition as defined in claim2 in which γ≦20.
 4. A dielectric ceramic composition as defined in claim3 in which 0.48≦γ≦10.
 5. A dielectric ceramic composition as defined inclaim 3 in which 0<γ≦10.
 6. A dielectric ceramic composition as definedin claim 5 in which said lead-based perovskite-type complex compound isless than 100 mol % of said dielectric ceramic composition.
 7. Adielectric ceramic composition as defined in claim 6 in which saidlead-based perovskite-type complex compound is about 10 to 52% of saidcomposition.
 8. A dielectric ceramic composition as defined in claim 2in which said lead-based perovskite-type complex compound is less than100 mol % of said dielectric ceramic composition.
 9. A dielectricceramic composition as defined in claim 8 in which said lead-basedperovskite-type complex compound is about 10 to 52% of said composition.10. A dielectric ceramic composition as defined in claim 1 in which saidlead-based perovskite-type complex compound is less than 100 mol % ofsaid dielectric ceramic composition.
 11. A dielectric ceramiccomposition as defined in claim 10 in which said lead-basedperovskite-type complex compound is about 10 to 52% of said composition.12. A dielectric ceramic composition as defined in claim 1 in whichγ≦20.
 13. A dielectric ceramic composition as defined in claim 12 inwhich 0.48≦γ≦10.
 14. A dielectric ceramic composition as defined inclaim 12 in which 0<γ≦10.
 15. A dielectric ceramic composition asdefined in claim 12 in which said lead-based perovskite-type complexcompound is about 10 to 52% of said composition.